Molten slags include, for example, molten blast furnace slag, molten converter slag, and molten electric furnace slag. It has been already known that it is possible to obtain a vitreous slag, for example, by cooling a molten blast furnace slag at a high cooling rate and thereby solidifying the same. The vitreous slag thus obtained is suitable, for example, as a cement material.
FIG. 1 illustrates a prior art apparatus for manufacturing rapidly cooled solidified slag, which is substantially the same as the apparatus for manufacturing a rapidly cooled solidified slag disclosed in U.S. Pat. No. 4,050,884 dated Sept. 27, 1977. In FIG. 1, 1 is an enclosed-structure housing. The housing 1 has an opening 1a at the top thereof for passing molten slag, and a discharge port 1b at the lower end thereof for discharging a rapidly cooled solidified slag having been crushed. In the housing 1, a pair of cooling drums 2 having the same diameter and the same length are arranged so that the axial directions thereof are parallel to each other in the same horizontal plane and the peripheral surfaces thereof are in contact with each other. Each of the pair of cooling drums 2 is rotated by a suitable driving means (not shown) in directions opposite to each other at the same peripheral speed as shown by the arrows "a" and "a'" in FIG. 1, in the rising direction of the peripheral surfaces thereof at the contact portion of the pair of cooling drums 2. A plurality of cooling through-holes (not shown) are pierced in the peripheral wall of each of the pair of cooling drums 2 in the longitudinal axial direction thereof. One end of each of the plurality of cooling through-holes communicates with the interior of a hollow portion (not shown) of one end of the center axle of the cooling drum, and the other end of each of the cooling through-hole communicates with the interior of a hollow portion (not shown) of the other end of the center axle of the cooling drum. The hollow portion (not shown) of the one end of the center axle of the cooling drum 2 is liquid-tightly connected to one end of a pipe 3 through a swivel joint (not shown). The other end of the pipe 3 is connected to the inlet of a steam drum 4. An end of another pipe 6 provided with a pump 5 is connected to the hot water outlet of the steam drum 4. In FIG. 1, 4a is an air feed valve of the steam drum 4 and 4b is a water supply valve of the steam drum 4. The other end of the pipe 6 is liquid-tightly connected to the hollow portion (not shown) of the other end of the center axle of the cooling drum 2 through another swivel joint (not shown). In FIG. 1, the steam drum 4 is connected to one of the cooling drums 2, and another steam drum (not shown) is similarly connected to the other cooling drum 2. As a result, by means of the pump 5, the cooling water for cooling the cooling drum 2 is supplied to the plurality of cooling through-holes of the periphery of the cooling drum 2 through the pipe 6 and the axle of the cooling drum 2. The cooling water supplied to the plurality of cooling through-holes is heated by the heat contained in the molten slag 7 deposited onto the peripheral surface of the cooling drum 2 as described later, and supplied to the steam drum 4 through the axle of the cooling drum 2 and the pipe 3 while partially generating steam. The pressurized steam supplied to the steam drum 4 is separated into steam and hot water in the steam drum 4. The hot water separated in the steam drum 4 is supplied again, as the cooling water, to the plurality of cooling through-holes of the peripheral wall of the cooling drum 2 through the pipe 6 by means of the pump 5. As a result, the cooling water circulates through the cooling drum 2 and the steam drum 4. The steam separated in the steam drum 4 is, on the other hand, used for driving, for example, a turbine (not shown).
A pair of weirs 8 are provided in the upper halves of the both ends of the pair of cooling drums 2 so as to be in contact with the both ends of the pair of cooling drums 2 (FIG. 1 shows only one of the pair of weirs 8). The top ends of the pair of weirs 8 are connected with each other through a cover 8' having at the center thereof an opening 8'a. The pair of weirs 8 and the cover 8' are supported on the housing 1 by means of a suitable supporting means (not shown). A slag sump 9 is formed by the bodies of the pair of cooling drums 2 and the pair of weirs 8. The molten slag 7 discharged from a slag runner 10 is poured into the slag sump 9 through the opening 1a of the housing 1 and the opening 8'a of the cover 8', where a slag pool is formed. The molten slag 7 poured into the slag sump 9 is deposited onto the peripheral surfaces of the cooling drums 2 during the rotation thereof, rapidly cooled and solidified substantially completely into a solidified slag. The cooling water supplied to the plurality of cooling through-holes of the peripheral wall of the cooling drum 2 is heated by the molten slag 7 deposited onto the peripheral surfaces of the cooling drums 2 and becomes hot water having pressurized steam. When the solidified slag 7' on the peripheral surfaces of the cooling drums 2 reaches the lower halves of the cooling drums 2 according to the rotation of the cooling drums 2, the rapidly cooled solidified slag 7' deposited onto the peripheral surfaces of the cooling drums 2 is peeled off therefrom, while being crushed by a scraper 11 supported on the housing 1 by means of a suitable supporting means (not shown), and drops into the lower part of the housing 1. A suitable opening and closing means (not shown) is provided in the discharge port 1a of the lower part of the housing 1. The peripheral surfaces of the cooling drums 2 from which the rapidly cooled solidified slag 7' has been peeled off by the scraper 11 comes again into contact with the molten slag 7 of the slag sump 9 according to the rotation of the cooling drums 2, whereby the rapidly cooled solidified slag is continuously manufactured.
FIG. 2 is a schematic sectional view illustrating an embodiment of the apparatus for manufacturing the rapidly cooled solidified slag according to the present invention. As shown in FIG. 2, in a housing 1, a cooling drum 2 is arranged so that the direction of the center axis thereof is horizontal. The cooling drum 2 is rotated by a driving means (not shown) in the direction of the arrow "a" shown in FIG. 2. A plurality of cooling through-holes (not shown) are pierced in the peripheral wall of the cooling drum 2 in the direction of the center axis thereof. One end of each of the plurality of cooling through-holes communicates with the interior of a hollow portion (not shown) of one end of the center axle of the cooling drum, and the other end of the cooling through-holes communicates with the interior of a hollow portion (not shown) of the other end of the center axle of the cooling drum. The hollow portion (not shown) of the one end of the center axle of the cooling drum 2 is liquid-tightly connected to one end of a pipe 3 through a swivel joint (not shown). The other end of the pipe 3 is connected to the inlet of a steam drum 4. An end of another pipe 6 provided with a pump 5 on the way is connected to the hot water outlet of the steam drum 4. In FIG. 2, 4a is an air feed valve of the steam drum 4, and 4b is a water supply valve of the steam drum 4. The other end of the pipe 6 is liquid-tightly connected to the hollow portion (not shown) of the other end of the center axle of the cooling drum 2 through another swivel joint (not shown). As a result, by means of the pump 5, the cooling water for cooling the cooling drum 2 is supplied to the plurality of cooling through-holes of the peripheral wall of the cooling drum 2 through the pipe 6 and the axle of the cooling drum 2. The cooling water supplied to the plurality of cooling through-holes is heated by the heat contained in the molten slag 7 deposited onto the peripheral surface of the cooling drum 2 as described later and supplied to the steam drum 4 through the axle of the cooling drum 2 and the pipe 3 while partially generating steam. The cooling water circulates through the cooling drum 2 and the steam drum 4 by means of the pump 5.
As shown in FIG. 2, in substantially the upper half of the cooling drum 2, a slag sump 9 is formed by: a slag receptacle 12 provided so as to be in contact with the cooling drum 2, and the drum body of the cooling drum at the rising position of the peripheral surface of the cooling drum 2. The slag receptacle 12 comprises a plate 12a, another plate 12b and a pair of plates 12c. The plate 12a has the longitudinal direction thereof parallel to the direction of the center axis of the cooling drum 2, with substantially the same length as the cooling drum 2, and is upright. The plate 12b has the longitudinal direction thereof parallel to the direction of the center axis of the cooling drum 2. One end of the plate 12b in the transverse direction is fitted to the lower end of the plate 12a, and the other end thereof in the transverse direction is in contact with the peripheral surface of the cooling drum 2. The plate 12b has substantially the same length as the cooling drum 2 and is horizontal. The pair of plates 12c are fitted respectively to the both longitudinal ends of the plate 12a and the plate 12b and are in contact with the both ends of the cooling drum 2. A cover 12' having an opening 12'a is fitted to the top ends of the plate 12a and the pair of plates 12c. The slag receptacle 12 and the cover 12' are supported on the housing 1 by a suitable supporting means not shown. The molten slag 7 discharged from a slag runner 10 is poured into the slag sump 9 through the opening 1a of the housing 1 and the opening 12'a of the cover 12', where a slag pool is formed. The molten slag 7 poured into the slag sump 9 is deposited onto the peripheral surface of the cooling drum 2 during the rotation thereof, rapidly cooled and solidified into a solidified slag. The cooling water supplied to the plurality of cooling through-holes of the peripheral wall of the cooling drum 2 is heated by the molten slag 7 deposited onto the peripheral surface of the cooling drum 2 into a hot water having a pressurized steam. When the rapidly cooled solidified slag 7' reaches the lower half of the cooling drum 2 according to the roation of the cooling drum 2, the rapidly cooled solidified slag 7' deposited onto the peripheral surface of the cooling drum 2 is peeled off therefrom while being crushed by a scraper 11 supported on the housing 1, and drops into the lower part of the housing 1. A suitable opening and closing means (not shown) is provided at the discharge port 1b in the lower part of the housing 1. The peripheral surface of the cooling drum from which the rapidly cooled solidified slag 7' has been peeled off by the scraper 11 comes again into contact with the molten slag 7 of the slag sump 9 according to the rotation of the cooling drums 2, whereby the rapidly cooled solidified slag is continuously manufactured.
According to the above-mentioned manufacturing apparatus of the rapidly cooled solidified slag, having a pair of rotating cooling drums 2 and the above-mentioned manufacturing apparatus of the rapidly cooled solidified slag, having a rotating cooling drum 2, it is possible to continuously manufacture the rapidly cooled solidified slag. However, any of the above-mentioned manufacturing apparatus has the following problems. It has been difficult to stably deposit a molten slag 7 onto the peripheral surface of the cooling drum and ensure peel off of the rapidly cooled solidified slag 7' obtained by rapid cooling and solidification of the molten slag 7 on the peripheral surface of the cooling drum 2 from the peripheral surface of the cooling drum 2. A low adhesion of molten slag 7 to the cooling drum 2, for example, leads to a lower cooling efficiency of the molten slag 7 on the peripheral surface of the cooling drum 2. As a result, for example, there is a decrease in the ratio of vitrification of solidified slag obtained by rapidly cooling and solidifying a molten blast furnace slag by the cooling drum 2. When the molten slag 7 has a low adhesion relative to the cooling drum 2, the molten slag 7 of the slag sump 9 is not deposited onto the peripheral surface of the cooling drum 2 during the rotation thereof, thus making it impossible to manufacture a solidified slag. For example, on the other hand, when adhesion of the molten slag 7 to the peripheral surface of the cooling drum 2 is strong, the peel off property of the rapidly cooled solidified slag from the peripheral surface of the cooling drum 2 is impaired, leading to a serious wear of the peripheral surface of the cooling drum 2 and the scraper 11. Particularly, in the case of the pair of cooling drums 2, solidified slag firmly adhering to the contact portion of the two cooling drums, thus causing more serious wear of the peripheral surface of the cooling drum 2 and the scraper 11.